<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    function pname () {
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          resolve('成功获取省份')
        }, 1000)
      })
    }
    function cname () {
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          resolve('成功获取城市')
        }, 1000)
      })
    }

    function aname () {
      return new Promise((resolve, reject) => {
        resolve('成功获取区')
      })
    }

    pname()
      .then(res => {
        console.log(res, 111);
        return cname()
      })
      .then(res2 => {
        console.log(res2, 222);
        return aname()
      })
      .then(res3 => {
        console.log(res3, 3333);
      })
  </script>
</body>

</html>